1. Field of the Invention
The present invention relates generally to electrical circuits, and more particularly but not exclusively to voltage regulators.
2. Description of the Background Art
A DC-DC converter is a voltage regulator that receives a DC input voltage to generate a regulated DC output voltage. A hysteretic DC-DC converter, such as bang-bang and non-synchronous converters, is a type of DC-DC converter that maintains the output voltage within a hysteresis range relative to a reference voltage. One problem encountered when implementing hysteretic DC-DC converters is related to their relatively poor noise immunity. Any ground coupled noise from switching transients tends to disrupt operation of the converter's input hysteretic comparator, causing erratic operation and even instabilities especially at high output current levels. One way of solving this noise-related problem is to perform comprehensive analysis of the converter's layout. However, good converter performance is difficult to achieve even with the most thorough layout analysis. Another solution is to provide a larger hysteresis window to reduce sensitivity to noise, but this adversely affects accuracy of regulation.